M6 bolt, so an M8 nut should slide over and be flush with the top of remaining stud. In the days before easy welding a hole would be drilled through the m8 hex to hex on the bench, usually a 2.5 mm hole. Nut slipped on and using the nut as a guide drill through remains of the stud. Nut can be held in place with epoxy to stop it moving when being used as a guide. The shaft of the 2.5 mm drill would then be used as a locking key to hold m8 nut to stud. Plenty of plus gas spray and a good grip on the nut and the stud can be removed. Freeze spray works around the stud. Space is the problem. Stainless is an answer but A4 not A2. A4 has a small percentage of moly in the mix giving better corrosion resistance and tensile strength in exhaust areas. Touch of copper slip on nuts on assembly, spare nuts in tool box. Rather lose one of my nuts than shear my stud!
Right!! They’re out - my new best mate with the welder got two out straight off, but had to drill out the last one, and helicoil. Lovely bloke - however, eyeballing a 6mm bolt I have tentatively checked the helicoil with, it looks to be very slightly off centre. From most angles it looks straight but from one side it looks off a bit....new studs are a way off, so no way to check it other than putting some regular bolts in to ensure it will fit which I can’t do before the weekend - has this happened to anyone else and was it a major issue or did it go together as it was tightened down? Final (potentially stupid) question but putting the new studs in...two nuts on and tighten down to 10Nm or is there a “proper” way to get them in I am not seeing?
It's pretty much impossible to hand drill out a broken stud for helicoil and get it properly centered and straight, You'll probably have to grind out the hole in the header flange. New studs should not be torqued to the same spec as the header flange nut, just turn them in slightly snug
10nm is about 7.4ftlb so pretty low, little finger on short spanner tight. But I suggest you copper slip the nuts. Helicoils rarely look central even if they are, so suck it and see by using your two studs loose in and seeing if the third helicoil lines up. Clearance is normally 6.25 mm in a tool room and 8 mm by a fitter,but you can always fettle the helicoiled flange out to fit. Seen it done but do not use nyloc nuts. Made no friends with fitters there!
hi - thanks for the reply, not sure I understand this part....what does this clearance measurement apply to? Will definitely use some copper slip per your previous advice, and carry spare nut in tool kit! cheers
The 6.5 is the hole size on the exhaust flange. 8mm hole is what cack handed fitters usually drill. An in joke, well almost!
I've been debating fitted a de-cat, but this is definitely putting me off! Just wondering if it may be better to pre-emptively cut the nuts off, to prevent issues with shearing the studs, then clean the studs up with a thread die? Any recommendations on where to order a replacement gasket and nuts?
In hindsight - I would have tried SERIOUS heat and penetrating oil over a day or three before even attempting to move the nut. With even more hindsight (or next time) I would try cutting if I could do it with no damage to the surrounding areas (Dremel or similar small wheel), I wouldn’t reuse the studs though so the only benefit would be more to grip on to with the stud extractor gadget, or more to use for the weld. will definitely be investing in a welder and practice over long term - such a useful thing to know how to do. Edit: If you want OEM: InMoto (Ducati-parts-online.co.uk) are still shipping, gasket and nuts are on route - although usual lack of comms and time taken are still evident. Still looking around for stainless studs before I decide.
I've ordered a butane torch off ebay. If I can get the nuts undone then I'll order a de-cat! Weirdly, I didn't have any issues whatsoever with them on my 2013 MTS.
which torch did you go for Nik? so many on the market and some better than others. I have no recommendations. Mine which is over 10 years old, is NLA.
It was literally just a £10 thing that comes with a removable/replaceable canister. Loads to choose from on there. I'm not expecting it to be much use if I'm honest, but figured it's better than nothing, and definitely worth a try. https://www.ebay.co.uk/itm/Blow-Tor...var=651247525679&_trksid=p2057872.m2749.l2649
I had a look at my exhaust studs yesterday. Managed to undo two of the three. The third was hard to get a socket on to it due to the curve of the exhaust, so I managed to round it off, unfortunately. Now debating cutting it off with a small Dremel cutting disc, being careful not to damage the stud!
I remember years ago not on a Ducati I managed to get a new sharp drill probably about 2mm and drill into one of the flats but careful not to go to far in, then with a very small sharp chisel I split the nut. I guess you could start with a 1mm drill then progress up until your happy and then knock it off.
Yes, that would work. Even a hacksaw would probably do the job. Fiddly little bastards - they seem unnecessarily small.
Got mine all back together now - took some persuasion with the one offset stud (was more off than I thought), but some heat and a bit of a chat with a wooden block and a rubber mallet and it was seated perfect. Next: battery brace and spinning captive nut...which I only discovered disconnecting my battery for the welding
